Deer management

A view on deer management and restoring natural processes in the Highlands

Deer and the Highland landscape

Deer are a natural part of our woodland ecosystems. They fulfil an important ecological role in diversifying woodlands. They open up glades, recycle nutrients, spread seeds in their dung and create space for young trees and plants to grow into. However, in many parts of the Highlands, browsing pressure from deer has become out of balance with vegetation growth, so that sustained browsing is preventing young trees from becoming established.

Overall populations of red, roe, sika and fallow deer in the Highlands have grown steadily since at least the 1960s[i], annually increasing the pressure on tree cover. In the areas where deer populations are too high, habitats and the wildlife which depend on them are degrading year on year, to the point that even the deer themselves are finding it harder to put on body weight. The result is that the ecological potential of the Highlands is all too rarely realised. Deer have become a landscape-scale suppressor of ecological processes in the Highland ecosystem.

Facilitating natural vegetation development

Reducing deer pressure across large areas would kick-start the development of a wider variety of natural vegetation and habitats[ii] across much of the Highlands. We do not expect, and would not wish to see, woodland habitats developing everywhere. Instead, large, open expanses of peatland, heath and grasslands would, together with woodlands and scrub, form a rich mosaic of habitats, with vegetation dispersing naturally from seed sources.

As a rough guide, natural regeneration rarely takes place where deer populations are higher than five deer per square kilometre. While this will vary with a number of habitat and environmental factors, the scale of deer reductions required will be very significant in many areas. It is widely believed that this could add to the financial stresses experienced by Highland estates, many of which currently act as foundations for fragile rural economies by attracting stalking clients who bring business to accommodation and other local services which are linked into wider supply chains[iii]. However, we believe these stresses can be short-lived and that new approaches to deer management can lead to a greater range of new business opportunities in the medium and long term. Moreover, deer thrive better at lower densities and there is a reliable and early prospect of bigger, healthier and higher value deer[iv], especially as the woodland ecosystem develops.

Combining deer management tools

On our own ground, we use three tools for managing deer and we advocate using these in different combinations to suit different circumstances. Deer management needs to take place over large areas, so communication and collaboration between neighbouring landowners is essential if these tools are to be effective and sustainable in the long term.

Culling – we advocate shooting that focuses on reducing deer populations by moving the sex ratio of hinds to stags towards 1 to 1. This can often reduce deer pressure while maintaining similar stag numbers for sporting interests. As far as possible, we aim to mimic natural predation by selectively culling the weakest animals in the herd.

Fencing – we often erect deer fencing to protect planted trees from deer or to allow natural regeneration to occur. This is expensive to construct and to maintain. While success is not guaranteed, effective fencing allows woodland to establish and we view it as a pragmatic step to take while deer densities remain at a higher level more widely across the landscape. We aim to remove fencing once deer densities in the area are low enough to allow natural regeneration of the forest to continue.

Disturbance – inspired by some of the impacts of predators on herbivore populations, we trialled deer scaring on our land at Dundreggan in 2016 (‘Project Wolf’), using volunteers to patrol specific parts of the woods to disturb the deer out of the areas where we most want to see regeneration. There are early signs that this is having a positive effect on regeneration, so this may be something we use more widely in the future as a substitute for fencing.

Monitoring to inform management

Understanding the relationship between habitat deer allows the use of these tools to be varied to move us towards the outcomes we want to see. We use a method of herbivore impact assessment to look directly at how much growth has been removed from a tree by browsing since the last growing season. It also allows an interpretation of the extent to which growth has been affected by browsing in previous years, so it is a very informative way of understanding the relationship between vegetation development and browsing. This allows us to judge whether or not we need to take action to reduce deer pressure to meet our aims.

As well as monitoring deer impacts, it is important to monitor the deer populations themselves. Deer counts, coordinated between neighbouring landowners provide useful snapshots of numbers and distribution. They can also provide information on calf survival and hind fecundity, which are key to understanding population recruitment rates. Understanding the movement of deer throughout the year is an important factor in management and detailed discussions among landowners are a good way to build this into collaborative deer management. Larder records are another key source of data, simply recording basic information like sex, broad age category, and carcass weight is a useful way to get an indication of how deer are faring on the habitat available.

Conclusion

Deer management polarises opinion in Scotland. Deer affect our environment, our sense of place, our enjoyment of the landscape and our rural economy in both positive and negative ways. The debate about these effects, and what we should do about them has led to discord between people on different sides of the argument. The conflict between sporting and conservation interests is now long-established, with trust and respect in short supply. We are mindful that there is much to learn about deer and their management in Scotland, so we will take this on board as research and learning brings greater knowledge into play.

We want to help find a basis for open, positive conversations with others about the most beneficial approach for the future, building on the new knowledge being brought into play from ongoing research about deer and their management. We remain open to new evidence that would contribute to our approach, and we hope others will take the same approach. We respect the fact that most people’s views are founded in a strong set of values and believe that these values are often closer than is apparent on the surface. It is our hope that a shared passion for, and delight in, the land, the prosperity it brings, its cultures and its wildlife can still bring the different sides of this debate together in finding a shared way forward.

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About Trees for Life

The core purpose and vision of Trees for Life is to restore the Caledonian Forest and all its constituent species of flora and fauna to the Scottish Highlands. By engaging volunteers to achieve this, we aim to provide a powerful and educational experience that will promote the work of restoration to wider audiences. Through providing a demonstration of the techniques of ecological restoration, we aim to inspire similar projects elsewhere in the UK and around the world.